The invention is in the field of inflation pumps and particularly relates to the inflation of low-pressure, low-volume inflatables such as volleyballs.
Commercially available manually operated pumps fall into two basic groups divided by by pressure rating. Low pressure pumps that are used for inflating air mattresses and inflatable boats, for example, are generally accordion- or bellows- like and operated with the foot like a treadle peddle. They are large and gangly because each gulp of air must be large enough that the air mattress inflation process lasts minutes rather than hours. These pumps may move a liter of air in each stroke, and though usually light enough in weight, between the wide connecting hoses and the sheer size and floppiness of the pumping chamber, they still rank relatively high in nuisance value.
At the high pressure end is the traditional bicycle pump and its progeny, used more for automobile tires than bicycles. Most of these pumps are capable of reaching the 90- to 120-pounds-per-square-inch of air pressure required by high performance racing bicycles. The pumps in this genus all operate on the same basic principle, having a piston and cylinder arrangement with a long piston shaft so that they are by their nature rigid.
Although it cannot be said that the well-designed, small cylindrical bicycle-mounted pumps are bulky, they are nonetheless bulky enough that they can not be conveniently stuffed into a pocket. Their rigidity and their axial size, even though they may be compact compared to ground-supported bicycle pumps, make them a nuisance to carry around to volleyball games. Like a hand axe, a folding stool or a belly board, the presence of the pump is just one more thing that must be lugged around and kept track of, one more piece of equipment in a gadget-weary world.
Almost all hand pumps divide along these lines, by pressure. There does not appear to be available a true hybrid pump, a bridge between two worlds and taking advantage of both. High pressure applications involve limited volumes of air, whereas pumps servicing the low pressure market are big on volume and weak in the pressure department, but how about applications which require neither high volume nor high pressure? A volleyball contains a six-inch cube of air at a pressure of 12 pounds per square inch. There is no available pump tailored specifically to applications in this range, servicing the crossover zone. And in particular, there is no pump that is designed specifically toward the unique needs of the volleyball player.
There are special considerations for volleyball that have to do with inflation. For example, in tournament play, both sides must agree on the pressure of the ball, with the pressure usually being checked by feel rather than numerically. If a bicycle pump is used, since it requires two-handed use, the player who is pumping the ball cannot feel the ball as it is being inflated so that he does not know when to stop. The other player may be feeling the ball, but the point at which he says "stop" may not satisfy the player doing the pumping. This can create a frustrating and antagonizing delay, if the ball is repeatedly over- or under-inflated before a mutually satisfactory pressure level is reached, since if the pressure does not satisfy both sides, the pumping has to start all over again. If the first player could at least feel the ball while pumping, he could discuss it with the other side, with both having a hand on the ball, and get it right the first time.
The ability to fine tune the pressure would be a great help. After over-inflating, incremental adjustments could be made, in small steps, until both sides agreed. But bicycle-style pumps are not subtle, they are either pumping, not pumping, or the needle adapter is unscrewed from the pump and the entire charge of air is gone in a "whoosh".